Neurons in brain operate constantly day after day. Electromagnetic waves (the so-called brainwaves) are transmitted among neurons. States of the brainwaves can be displayed through an electroencephalogram (EEG).
Specifically, an EEG is a diagram that records the potential difference of two points on a skull changing with time, usually in micro-volts. Generation of the potential difference relates to potential of the membrane. There are potential differences between both sides of the cell membrane. The extra negative ions in a cell attract positive ions outside the cell, and thus form the potential on the inner and outer layers of the cell membrane. The potential difference recorded by the EEG is collectively created by the thousands of neurons near the surface of the cerebral cortex, and is the consolidated potential of the majority of brain cells for a specific period of time, rather than the potential change of a single brain cell.
The potential change of neurons in brain recorded by measuring the brainwave may determine whether there is abnormal discharge or potential abnormal of the brain function, and can be used as a physician diagnosis, such as diagnosis of epilepsy, central nervous system or dementia psychosis. However, when measuring the brainwave, in order to pursue high spatial resolution to facilitate diagnosis, more measurement channels are used to improve the spatial resolution of the brainwave. An independent component analysis method is effective for separating independent component signal of the brainwave and the noise. However, in performing high channel independent analysis for the brainwave in the portable medical equipment, computation and complexity of the hardware are quite huge. It is a challenge for persons in the art to achieve an effective real time brainwave analysis, while taking into consideration the volume and hardware costs
Therefore, there exists a need to achieve the real time analysis of the brainwave independent component by the hardware in a portable device.